Just hit the report button on their profile if you think they're cheating and just play fairly.
Cheating

There's a really cool club called "Cheating Forum" that would be more suitable for this topic.
No one really wants to hear about that kind of stuff here.

I wanted to be helpful, but after seeing this and your ratings, I really just didn't know what to say!?!

When I suspect someone cheating, I report and block him. Usually 1 in 5 cases I'm right.
what about the other 4?
other times they arent cheating and just played a suspicous game. no harm in it
As others have said, if you think someone is cheating, report them and move on. Chess.com will either determine they were cheating, give you your points back and close their account or determine they were not cheating and the account is closed and the world turns with no harm done.
All you can do is keep improving to the 3751 level so you can beat cheaters, or just flag them in bullet.

Perhaps if you wish to enjoy chess more, you should explore learning and improving at chess rather than getting bogged down calling 400s cheaters. Most cheaters would probably be closer to 1800+ elo. A good goal for you could be reaching 1000 elo. The question of how to begin improving at chess is a whole other topic so I won't cover it here.
People are cheating and I am being accused because you can't control them. Not impressed!!!